An angel giving John a tour of heaven showed him "a pure river of water of life, clear as crystal, proceeding from the throne of God and of the Lamb. In the middle of its street, and on either side of the river, was the tree of life, which bore twelve fruits, each tree yielding its fruit every month" (Revelation 22:1-2).
"Every month" directly implies time in heaven.
After an introduction to "the great city, the holy Jerusalem," and a detailed examination of the city, its 12 gates, and its walls, John observed, "But I saw no temple in it, for the Lord God Almighty and the Lamb are its temple. The city had no need of the sun or of the moon to shine in it, for the glory of God illuminated it. The Lamb is its light. And the nations of those who are saved shall walk in its light, and the kings of the earth bring their glory and honor into it. Its gates shall not be shut at all by day (there shall be no night there). And they shall bring the glory and the honor of the nations into it" (Revelation 21:22-26).
Two key important parts of this are restated a few verses later: "There shall be no night there: They need no lamp nor light of the sun, for the Lord God gives them light" (Revelation 22:5).
These do not say there is no sun or moon, but that there is "no need" of the sun or of the moon. The second instance contains an additional word that implies we won't have a desire to hold on to a light as that will be completely unnecessary.